Fluid pressure operated motor



Patented Dec. 9, 1952 VUINII'TIED i 'STATE' S AT ENT oli-#Fica .FLUID:PRESSURE oPERA'rEnMo'roR WilliamA:Ray,-North-Hollywood, Califgassignorto General l(Jon-trols Co., Glendale, Califg-a'corsporationQof:California reApplication July, 1951, .Serial No.2.35.,.467

(on ca -52) ceding Obj ect which, employs an elastic iiuidsuch escompressed air.' .both .forits operation. and' for its control.

Another .cbjeotis '.to `proyidea pneumatically operated andl controlledmotorwhose actuating memberishydraulically operated and locked inposition.

For full understanding of' the invention, and further ,appreciation ofits A'objects Aand advantages, referenceis'` to 'be iha'd ,to jthefollowing .j detailed description and accompanying drawing. andtotheappended claims.

'Ifhe single 'gureof the drawing is a sectional view of a'uid pressuremotor embodying 4the inventorl; the figure including a diagrammaticshowing of a conventionaVvalve positione1""for controlling the motor.

The motor structure shown in the drawing comprisesa disk-like basev llhaving ,a vplurality of'legs l2 for attaching the structureyvtoa devicetoQbe operated, such as a fluid control valve. Mounted on top of thebase is a main pressure.- motor Ai3 which comprises a cylinderIasealingly secured jto thebase, and a cooperating plunger Irhaving astem i6 sealingly extending through an opening in the base forconnection to the stem ofthe device to be operated. The space around themotor I3 is iconi-lnedby a tubular housing l1, secured t o the`periphery of base ll, to provide a reservoir ljfor'hydraulic uld foroperation 'of this motor;y the surface of 'this' fluidbeingindicated-by'the'legend OilleVeL On'top of the motor cylinder M,and secured thereto by vits anged'base 19, 'is a pump structure 20havinga'bore '2 1 Vfor a reciprocable piston 22. jIn `the side of thepumpstructure isa slot 23through-which liquid from the reservoir .I8 entersthe' bore V2lwhen the piston 22 is lin* the position shown and, whenvthepiston is moved downwardly (by/means tobe described) vforced througha `passage 24" vair-the bottom of" the bore structure ris ahuid-pressure reciprocating jm chamber-38 the space below the 35 packingmember 44.

into a `chamber325 and' thence-to Y'the spaelpr pressure chamberZSbelcwthe plunger: L5 orfthe main pressure-,motor :bywvay of Zaspipeiz'linteliconnecting these .chambers; acheck lvalve2 8, bia-sed by aspringiinto engagementwithja seat formed'at the, bottom ofpassage'd, preuent.-ing return `of :the v,liquid When'the piston f2? 'isretracted.

.Pumoins 0f liquid .into the space' .126' belowtbe plunger .Causes .the.sam-eet@ riseaeainsttherorce 0fy a lserine 'zcompressodi betweenihopliniger alldthelbase |.9' Of 511613111913 .Strlllll th'ell aboverihev,runser being infree communication withv the reservoirrbyrway of anVopening". 31 in the .upper jpart of 'cylinder 1 4. jgAj-projection-32of the'mctor stemi limits 'upwardlmovemerlt of the plunger.

`v'lhe chamber' 2e vbelow' the purnpfis 'also gonnecredby a bentpipeiioanoponiog 'leadins to 'the piston 100.17621 eiaponibsrondrthe renee of vpumping movementof -piston'I 22, so that when (in a mannerto-bedescribed) vthe-pistonisjraised slightly above :its positionvasshown 1in thejdrawing fluid can escape fromithe'rnainemotorcham- 25,pipe l3S, opening-3d, 'bore-2l 'and s101123.; :the plungerlfalling underfthe force ofgspringep.

On 'the .dished top Lportion 35 of ':iheipunip tor, or pulsator, 5Bwhich comprises ia, v:flexible phragm lSle'clarnped at-itsVinarginibetweenthe dished portion'ii and aninverted dished-member 31which defines with the 4diaplrragrrr apressure diaphragm-beingvented toatmosphere-bilanopening 91 "'Ihe central part or Vdiapliragmfi -is'clarnped tolithe upper end of piston 22 by a nume-threaddlon the top4extension-tl of 4kthe -pistonffs'tiiien-ing n platesiar being.provided'oneither side o'f the 'iiajphragin.

The vdiapl'iragin 'and' piston assembly-is biased upwardly bya-springs-B encirclingiythepiston and bearing at Vits `bottom -ona-conventional above the diaphragrnis Iat atmospheric--pressure thetopyofpiston-extension ll-l isdn engagement with the 'member-3i undereitheforce-offspring 43 ;-it beingvassumed that with the lparts jinv'kthepositions sho-wn .in the-drawingthe pressn'rerin chamber A'-33 isslightly -in 1excessofw atmospheric, aswillvbe described.

For supplying pressure -iiuid to thechamher I of the-reciprocatir-1glmotor,A Iand for'ventingi'it,

.there is a--Kpair of alignedLvalve-jets *45 -^and^-46 projecting -intothe-chamber; `the lowerljete When the chamber being secured in openingsthrough the dished members 31 and 35 and communicating with a threadedrecess 41 in the latter, the other jet 46 being threaded in an openingthrough the top wall of member 31. The jet 46 leads directly toatmosphere, but in the event that a uid such as high-pressure fuel-gasis employed for the reciprocating motor, the recess 48 with which jet 46communicates may be threaded for the connection of means for utilizingthe gas.

Between the jets 45 and 46, and alternately cooperable with theindividual jets, is a dualended closure 49 carried by an arm 50 whoseleft-hand end is fulcrumed in the root of a notch provided in theright-hand end of a lever 52 which is pivoted on a pin 53 projectingfrom a bracket 54 attached to the member 31. As shown in the drawing,the right-hand end of arm 50 is urged in upward direction by a spring 55tensioned between the arm and pivot pin 53 so that closure 49 is held inengagement with the upper jet 46; the closure being so mounted on arm 55that it is free to conform to the plane of the tips of the jets. Thisupward tension on arm 58 is due to the fact that the left-hand edge ofthe arm (fulcrumed in notch 5l) is slightly below the line of force ofspring 55. The rounded lefthand end of lever 52 is supported by agrooved collar 56 threaded on the piston-extension 4l (and locked inadjusted position, as by a through pin, not shown) so that when thepiston moves downwardly (as will be described) the lever 52 is rockedcounterclockwise. When the position of the lever then becomes such thatthe root of notch 5I is just above the line of force of spring 55 (thebottom of piston 22 being just above the level indicated at A) the arm50 is snapped to its alternate position with closure 49 in engagementwith the lower jet 45. The lever 52 consists of two like portions joinedtogether at the top by a bridge 51 and spaced apart sB-that theleft-hand ends of the lever are in the groove of collar 56 and atopposite sides thereof; the arm 56 being bifurcated s0 that it has twoleft-hand ends which rest in the notches in the right-hand side portionsof lever 52.

At the right of the motor structure, and generally indicated by thenumeral 60, are means for supplying fluid, such as compressed air, tothe reciprocating motor 58, and for regulating the supply of fluid inresponse to variations of a condition, such as temperature or pressure,which variations require corresponding variation of the position of thevalve or other device connected to the main-motor stem I6. The means 60are of conventional design and are therefore shown diagrammatically.

The numeral 6l indicates a stationary member to opposite sides of whichone end of a bellows 62 and of another bellows 63 are attached; thebellows carrying at their other ends heads 64 and 65 which are rigidlyinterconnected by a rod 66 extending freely through an opening 81 in themember 6|.

The space around the bellows 63 and its head 65 is enclosed by a housing61 to provide a pressure chamber 68 which is connected by a pipe 69 to asource of pressure iiuid (conveniently, compressed air) indicated by thelegend. Branching from the pipe 69 is a jet 10 with which a movableinstrument arm 1l cooperates. A fixed restriction 12 is provided in pipe69 ahead ofjet 10, so that when the arm 1I is rocked away from the jetthe iiuid passing the restriction can readily escape through the jet andthe pressure '4 applied to chamber 68 is substantially atmospheric; thepressure in the chamber increasing as the arm 1l is moved toward the jetand becoming equal to that of the source when the jet is closed by thearm. The arm 1I corresponds to the movable element of acondition-responsive instrument such as a thermostat.

The fluid pressure in chamber 63 acts on the bellows head 65 to move it,and the interconnected head 64, toward the left; such movement, however,being opposed by the force of a spring 13 compressed between head 64 and(through a disk 14) the tip 15 of a bell-crank lever 16 whose lower armis connected by a, link 11 to the mainmotor stem I6.

The stationary member 6I has a vertical passage 18 which is connected bya pipe 19 to a source, indicated by the legend, of operating pressureiiuid which may be high-pressure air; the passage 18 having at its innerend a branch opening 80 with which a conical closure 8l cooperates. Thisclosure is connected by a stem 82 to a similar closure 83 whichcooperates with a vent opening 84 through the bellows head 64, theclosure assembly being biased toward the right by a spring 85. Thearrangement is such that both of the closures 8| and 83 are seated whenthe opposing forces acting inwardly on the bellows heads 64 and 65 arebalanced. When, due to the unbalance of these forces, the bellowsassembly is moved toward the left closure 8| is unseated; closure 83being unseated when the assembly is moved toward the right. In the topof member 6l is a, vertical passage 86 which joins the transverseopening 81 and is thus in communication with the interior of bellows 62and 63; passage 86 being connected at its outer end to a pipe 83 whichextends to the inlet fitting 41 of the reciprocating motor 58.

From the foregoing it is clear that with rise of instrument pressure inchamber 68 operating pressure-huid is supplied to the reciprocatingmotor; and with fall of instrument pressure the inlet of thereciprocating motoris connected to atmosphere. It is to be observed thatoperating pressure-fluid within the bellows acts equally and oppositelyon the heads 64 and 65 and therefore does not tend to alter the positionof the bellows assembly.

As shown in the drawing the parts are in the positions taken when theinstrument arm 1| is in a low-pressure producing position; the pressurein diaphragm chamber 38 is correspondingly low (but not atmospheric) thepiston 22 is at the top of its pumping stroke (position B); and the mainpressure-motor stem I6 is in its lowermost position.

Assuming now that the instrument arm moves closer to jet 10: theresultant rise of pressure in chamber 68 eiects movement of the bellowsassembly toward the left so that closure 8l is unseated Vand operatingpressure-duid passes to the reciprocating motor, forcing the diaphragmand piston 22 downwardly. Just before the piston reaches the end of itsdownward or pumping stroke (position A) arm 50 is snapped to itsalternate position so that the closure 49 is moved out of engagementwith jet 46 and into engagement with jet 45. The resultant venting ofchamber 38 permits the diaphragm and piston to rise rapidly under theforce of spring 43. But just before the piston reaches its B positionthe position of arm 56 and closure 48 is reversed so that pressure abovethe diaphragm again rises and the pumping stroke is repeated; eachdownwardgmovementgofthe pistongforcing oilgfrom the reservoirto the.chamber 26 vbelow the plunger |15 -s o `that theisame rises. `Theaccompanying ,up- Walid movement. of stem |16 effectsclockwise rotationof bell-.crank i6 so that the force of spring I3-is increased andathebellows assembly moves toward the right to eifect reseating of'closure BI, s o-that-:operation `of `the `reciprocating motor ceases ythepressureof the 'fluid trapped in chamber 38 vmaintainingthe ,diaphragm andpiston stationary at some vposition within the pumping range, such asthegpositi-onshown in the ldrawmg.

If the instrument pressure in chamber G81-continuesnto rise 'the closure3l will be again unseatediandfthe pumping operation repeated untilthe'main-motor stemrises toa position `wherein the. ;force ;of spring 13vhas vbeen Vincreased `suiiiciently to balance the higher opposing fluidpressurein chamber (58;` itbeing assumed that the pressure oftheoperating lfluid vsupplied Sto the reciprocating motor is high enoughthat the increaseof forceof the bias springtl as theplunger rises isvanegligible factorinthe operation of lthe System.

Ifthepinstrument arm Vnow moves farther from .let HL- the resultantreduction of pressure in chamber 6 8 permits the bellows assembly tomove liQWald the right under the force of spring 73, andthe vent closure83 is unseated. When this occurs .the diaphragm chamber 38 is Ventedthrough jet.45,.pipe 83, the interior of bellows E2, 6 3, and opening 84; it beingassumed that jet45 was open, sinceitnat jet is closedonlyduring the brief. lreturn stroke of the .piston under the ,force Aofspring 43.

This venting of chamber 38 by the controlap.- paratus 68 f permits thediaphragm .and piston ato risetofull extent under .the `force of spring43; thepiston-extension 4l .then being in engagement with member 3.1 andthe-bottom of the piston in itsC position (closure 39 remaining inengagement with jet 46). The liquid under pressure in chamber 26 belowthe 4plunger now escapes ythrough the. opening 3d, which opening isclosed bythe Vlower portion of the pistonr 22 except when thepressure inchamber 38 is at, or only slightly above, atmospheric. The resultant fall of Vplunger l 5 effects reduction ofthe force Yof spring 13 tocompensate for the reduction/of pressurein chamber 68 (which caused theAoperation just described) and the bellows assembly returns to itsbalanced position wherein both of the closures 83 and 8l are seated.

'summarizing the foregoing description of operation: with rise ofinstrument pressure, pressure fluid issupplied to the reciprocatingmotor 58 so that the pump piston 22 is reciprocated to force liquid tothe space below plunger l5, causing the same to rise until the resultantincrease of force of spring 'I3 balances the instrument pressure,whereupon operation of the pump ceases due to seating of closure 8|.With fall of instrument pressure, the reciprocating motor is vented sothat the piston 22 rises above its pumping range to permit venting,through the opening 34 then uncovered by the piston, of liquid from themain pressure-motor so that plunger l5 falls until it reaches a positionwherein the opposing forces acting on bellows 62, 63 are again balancedand the vent-closure 83 seated. In this manner the valve, or otherdevice, connected to stem I6 is operated to positions corresponding tothose of the instrument arm 1l, and is locked securely in :thoseVpositions due lrto the trapped liquidr which fills thespace below theplunger.

In theevent of leakage from the Vmain-:motor chamber 26 or from thediaphragm chamber38, the resultant fall of stem I6 effects unseatingofclosure 3| so that additional pressure luidzis supplied to thereciprocating motorand liquid Vis pumped in an Vamount sufcient toreturn the stem I6 to its Yprevious position (assuminguthat theinstrument pressure hasremained'constanil). It is to be observed thatthe opening 34 ferventing the hydraulic-fluid is located close to thetop of theV pumping range of the piston so that the vent is uncovered bythe piston uponsmall reduction of pressure above the diaphragmp-thesystem. therefore responding quickly tothe slightest opening of ventclosure 83. rIhe follow-up spring vi3 is preferably arranged so that itsforce becomes suilcient tobalance the maximum-available instrumentrpressure just vbefore the-mainmotor stem I6 reaches its limit ofupwardmovement.

The rate of operation of `.the 'reciprocating motor and pump isgenerallynproportional.to the magnitude of increase of instrumentpressure which initiated that operation, since with a large increase ofinstrument pressure the closure 3l will be withdrawn far from its seatso that the pressure drop thereacross will be vsmall andthe fluid willbe supplied to the diaphragmlchamber at correspondingly high pressure.

The specific embodiment of -my invention vherein shown and described isobviously susceptible of modification without departing from the spiritof the invention, and I intenditherefore to be limited only by the scopeof the appended claims.

I claim as my invention:

1. In combination: a main lpressure-motor comprising a movable memberadapted to beconnected to a device to be positioned, and biased -to oneposition; a pump for forcing fluid to said motor and fluidly connectedto the motor so that operation of the pump effects gradual movement ofsaid member toward an opposite position against the force of said bias;a duid-pressure reciprocating motor for operating said pump and adaptedto be connected to a controlled supply of pressure fluid, saidreciprocating motor comprising a movable wall operatively connected tosaid pump, and valve means actuated by movements of said wall rwhen thesame is .adjacent opposite ends of its range of movement for so applyingsaid pressure iluid to the wall that, when the pressure of ,that'uid isin excess of a predetermined minimum amount, the wail is automaticallyreciprocated in said range to opcrate the pump; and ymeans responsive tothe pressure of the fluid supplied to said reciprocating motor andeffective, when that pressure falls below said minimum amount, to ventsaid main pressure-motor so that said member can move toward its biasedposition.

2. The combination defined in claim 1, and wherein said means forventing said main pressure-motor comprises valve means actuated bymovement of said reciprocating-motor wall.

3. The combination defined in claim 1, and wherein saidreciprocating-motor wall is biased toward one position, and. said meansfor venting said main pressure-motorcomprises valve means actuated bymovement of said wall to said one position.

4. The combination defined in claim 1, and wherein said pump comprises apiston, connected to said reciprocating-motor wall, and a cooperatingcylinder; and wherein the vent for said main pressure-motor is formed byan opening in the Wall of said cylinder positioned so that it is closedby the piston in its pumping stroke.

5. In combination: a main pressure-motor comprising a. movable memberadapted to be connected to a device to be positioned, and biased to oneposition; a pump for forcing fluid to said motor and fluidly connectedto the motor so that operation of the pump effects gradual movement ofsaid member toward an opposite position against the force of said bias;a duid-pressure reciprocating motor for operating said pump and adaptedto be connected to a controlled supply of pressure fluid, saidreciprocating motor comprising means dening a pressure chamber having amovable Wall biased toward one position and operatively connected tosaid pump, and valve means actuated by movements of said wall when thesame is adjacent opposite ends of its range of movement for alternatelyapplying said pressure fluid to the Wall and venting said chamber sothat, when the pressure of that fluid is in excess of a predeterminedminimum amount, the wall is automatically reciprocated in said range tooperate the pump; and means responsive to the pressure of the fluidsupplied to said reciproeating motor and effective, when that pressurefalls below said minimum amount, to vent said main pressure-motor sothat said member can move toward its biased position.

6. The combination deiined in claim 5, and wherein said means forventing said main pressure-motor comprises valve means actuated bymovement of said reciprocating-motor wall to its biased position.

7. The combination dened in claim 5, and wherein said pump comprises apiston, connected to said reciprocating-motor wall, and a cooperatingcylinder; and wherein the vent for said main pressure-motor is formed byan opening in the Wall of said cylinder positioned so that it is closedby the piston in its pumping stroke.

8. In combination: a main pressure-motor comprising a movable memberadapted to be connected to a device to be positioned, and biased to oneposition; a pump for forcing fluid to said motor and fluidly connectedto the motor so that operation of the pump effects gradual movement ofsaid member toward an opposite position against the force of said bias,said pump comprising a reciprocable piston and means forming a cylindertherefor; a fluid-pressure reciprocating motor for operating said pumpand adapted to be connected to a controlled supply of pressure fluid,said reciprocating motor comprising means dening a pressure chamberhaving a movable Wall biased toward one position and operativelyconnected to said piston, as Well :as valve means actuated by movementsof said Wall when the same is adjacent opposite ends of its range ofmovement for alternately applying said pressure fluid to the Wall andventing said chamber so that, when the pressure of that fluid is inexcess of a predetermined minimum amount, the Wall is automaticallyreciprocated in said range to operatethe pump; and means for ventingsaid main pressure-motor so that said member can move toward its biasedposition, said last-named means comprising additional valve meansactuated by said Wall when, in response to reduction of pressure in saidchamber below said minimum amount, the Wall moves under the force of itsbias to a position beyond its range of pumping movement.

9. The combination dened in claim 8, wherein the Vent for said mainpressure-motor is formed by an opening in the Wall of said cylinderpositioned so that it is closed by the piston in its pumping stroke.

l0. In combination: a main pressure-motor comprising a movable memberadapted to be connected to a device to be positioned, and biased to oneposition; a pump for forcing liquid from a source thereof to said motorand fluidly connected to the motor so that operation of the pump effectsgradual movement of said member toward an opposite position against theforce of said bias, said pump comprising a reciprocal piston and meansforming a cylinder therefor, said cylinder having in its side-wall anopening for entrance of liquid from said source when the piston isretracted and closed by the piston 1n its pumping stroue; a:luid-pressure reciprocating motor for operating said pump and adaptedto be connected to a controlled supply of gaseous pressure-huid, saidreciprocating motor comprising means dening a pressure chamber having amovable wall biased toward one position and operatively connected tosaid piston, and valve means actuated by movements of said wall when thesame is adjacent opposite ends of its range of movement for alternatelyapplying said pressure fluid to the wall and venting said chamber sothat, when the pressure of that fluid is in excess of a predeterminedminimum amount, the Wall is automatically reciprocated in said range tooperate the pump; and means for venting liquid from said mainpressure-motor so that said member can move toward its biased position,said last-named means comprising an additional opening in said cylindersidewall positioned so that it is normally closed by said piston and isuncovered by the piston only when, in response to reduction of pressurein said chamber below said minimum amount, said movable Wall is movedunder the force of its bias to a position beyond its range of pumpingmovement.

WILLIAM A. RAY.

No references cited.

